XC9235/XC9236/XC9237 Series

Transcription

1 XC9235/XC9236/XC9237 Series ETR mA Driver Tr. Built-In, Synchronous Step-Down DC/DC Converters GENERAL DESCRIPTION APPLICATIONS Smart phones / Mobile phones Bluetooth Mobile devices / terminals Portable game consoles Digital still cameras / Camcorders Note PCs / Tablet PCs FEATURES Driver Transistor Built-In Input Voltage Output Voltage High Efficiency Output Current Efficiency: Efficency:EFFI(%) EFFI GreenOperation Compatible The XC9235/XC9236/XC9237 series is a group of synchronous-rectification type DC/DC converters with a built-in 0.42 P-channel MOS driver transistor and 0.52N-channel MOS switching transistor, designed to allow the use of ceramic capacitors. Operating voltage range is from 2.0V to 6.0V (AC types), 1.8V to 6.0V (DG types). For the D/F types which have a reference voltage of 0.8V (accuracy: 2.0%), the output voltage can be set from 0.9V by using two external resistors. The A/B/C/E/G types have a fixed output voltage from 0.8V to 4.0V in increments of 0.05V (accuracy: 2.0%). The device provides a high efficiency, stable power supply with an output current of 600mA to be configured using only a coil and two capacitors connected externally. With the built-in oscillator, either 1.2MHz or 3.0MHz can be selected for suiting to your particular application. As for operation mode, the XC9235 series is PWM control, the XC9236 series is automatic PWM/PFM switching control and the XC9237 series can be manually switched between the PWM control mode and the automatic PWM/PFM switching control mode, allowing fast response, low ripple and high efficiency over the full range of loads (from light load to heavy load). The soft start and current control functions are internally optimized. During stand-by, all circuits are shutdown to reduce current consumption to as low as 1.0A or less. The B/F/G types have a high speed soft-start as fast as 0.25ms in typical for quick turn-on. With the built-in UVLO (Under Voltage Lock Out) function, the internal P-channel MOS driver transistor is forced OFF when input voltage becomes 1.4V or lower. The B to G types integrate C L discharge function which enables the electric charge at the output capacitor C L to be discharged via the internal discharge switch located between the L X and V SS pins. When the devices enter stand-by mode, output voltage quickly returns to the V SS level as a result of this function. Four types of package SOT-25, USP-6C, USP-6EL and WLP-5-03 are available. TYPICAL APPLICATION CIRCUIT XC9235/XC9236/XC9237 A/B/C/E/G types (Output Voltage Fixed) XC9235/XC9236/XC9237 D/F types (Output Voltage Externally Set) : 0.42 P-ch driver transistor 0.52 N-ch switch transistor : 2.0V ~ 6.0V (A/B/C types) 1.8V ~ 6.0V (D/E/F/G types) : 0.8V ~ 4.0V (Internally set) 0.9V ~ 6.0V (Externally set) : 92% (TYP.)* : 600mA Oscillation Frequency : 1.2MHz, 3.0MHz (+15%) Maximum Duty Cycle : 100% Control Methods : PWM (XC9235) PWM/PFM Auto (XC9236) PWM/PFM Manual (XC9237) Function : Current Limiter Circuit Built-In (Constant Current & Latching) Capacitor Operating Ambient Temperature Packages C L Discharge (B/C/D/E/F/G types) High Speed Soft Start (B/F/G type) : Low ESR Ceramic Capacitor :-40 ~ +85 : SOT-25 (A/B/C types only) USP-6C USP-6EL(A/B/C types only) WLP-5-03(A/B types only) Environmentally Friendly : EU RoHS Compliant, Pb Free * Performance depends on external components and wiring on the PCB. TYPICAL PERFORMANCE CHARACTERISTICS Efficiency vs. Output Currentf OSC =1.2MHz, VOUT=1.8V 100 PWM/PFM Automatic Sw itching Control VIN= 4.2V V PWM Control V VIN= 4.2V 3.6V V Output Current:IOUT(mA) 1/34

2 XC9235/XC9236/XC9237 Series PIN CONFIGURATION SOT-25 (TOP VIEW) * Please short the V SS pin (No. 2 and 5). * The dissipation pad for the USP-6C package should be solder-plated in recommended mount pattern and metal masking so as to enhance mounting strength and heat release. If the pad needs to be connected to other pins, it should be connected to the V SS (No. 5) pin. WLP-5-03 (BOTTOM VIEW) PIN ASSIGNMENT PIN NUMBER SOT-25 USP-6C/USP-6EL WLP-5-03 PIN NAME FUNCTIONS V IN Power Input 2 2, 5 3 V SS Ground CE / MODE High Active Enable / Mode Selection Pin V OUT Fixed Output Voltage Pin (A/B/C/E/G types) FB Output Voltage Sense Pin (D/F types) Lx Switching Output 2/34

3 XC9235/XC9236/XC9237 Series PRODUCT CLASSIFICATION Ordering Information XC9235 *1 XC9236 *1 XC9237 *1 Fixed PWM control PWM / PFM automatic switching control Fixed PWM control PWM / PFM automatic switching manual selection DESIGNATOR ITEM SYMBOL DESCRIPTION - Fixed Output voltage (V OUT ) Functional selection A B C E G V IN 2.0V, No C L discharge, Low speed soft-start V IN 2.0V, C L discharge, High speed soft-start V IN 2.0V, C L discharge, Low speed soft-start V IN 1.8V, C L discharge, Low speed soft-start V IN 1.8V, C L discharge, High speed soft-start Adjustable Output voltage (FB) D V IN 1.8V, C L discharge, Low speed soft-start Functional selection F V IN 1.8V, C L discharge, High speed soft-start Fixed Output Voltage (V OUT ) Adjustable Output Voltage (FB) Oscillation Frequency Packages (Order Unit) 08 ~ C D MR MR-G ER ER-G 4R-G 0R-G Output voltage options e.g. V OUT =2.8V=2, =8 V OUT =2.85V=2, =L 0.05V increments: 0.05=A, 0.15=B, 0.25=C, 0.35=D, 0.45=E, 0.55=F, 0.65=H, 0.75=K, 0.85=L, 0.95=M Reference voltage is fixed in 0.8V =0, =8 1.2MHz 3.0MHz SOT-25 (*2) (3,000/Reel) SOT-25 (*2) (3,000/Reel) USP-6C (3,000/Reel) USP-6C (3,000/Reel) USP-6EL (*2) (3,000/Reel) WLP-5-03 (*3) (3,000/Reel) (*1) The -G suffix denotes Halogen and Antimony free as well as being fully EU RoHS compliant. (*2) SOT-25, USP-6EL package are available for the A/B/C series only. (*3) WLP-5-03 package is available for the A/B series only. 3/34

4 XC9235/XC9236/XC9237 Series BLOCK DIAGRAM XC9235 / XC9236 / XC9237 A Series XC9235 / XC9236 / XC9237 B/C/E/G Series XC9235 / XC9236 / XC9237 D/F Series NOTE: The signal from CE/MODE Control Logic to PWM/PFM Selector is being fixed to "L" level inside, and XC9235 series chooses only PWM control. The signal from CE/MODE Control Logic to PWM/PFM Selector is being fixed to "H" level inside, and XC9236 series chooses only PWM/PFM automatic switching control. Diodes inside the circuit are ESD protection diodes and parasitic diodes. ABSOLUTE MAXIMUM RATINGS Ta=25 PARAMETER SYMBOL RATINGS UNIT V IN Pin Voltage V IN ~ 6.5 V Lx Pin Voltage V Lx ~ V IN V V OUT Pin Voltage V OUT ~ 6.5 V FB Pin Voltage V FB ~ 6.5 V CE / MODE Pin Voltage V CE ~ 6.5 V Lx Pin Current I Lx ±1500 ma SOT Power Dissipation USP-6C 120 Pd USP-6EL 120 mw WLP Operating Ambient Temperature Topr - 40 ~ + 85 Storage Temperature Tstg - 55 ~ O C O C 4/34

5 XC9235/XC9236/XC9237 Series ELECTRICAL CHARACTERISTICS XC9235A18Cxx/XC9236A18Cxx/XC9237A18Cxx, V OUT =1.8V, f OSC =1.2MHz, Ta=25 PARAMETER SYMBOL CONDITIONS MIN. TYP. MAX. UNIT CIRCUIT Output Voltage V OUT V IN =V CE =5.0V, I OUT =30mA V Operating Voltage Range V IN V Maximum Output Current UVLO Voltage I OUTMAX V UVLO V IN =V OUT(E) +2.0V, V CE =1.0V, When connected to external components (*9) ma V CE =V IN, V OUT =0V, Voltage which Lx pin holding L level (*1, *11) V Supply Current I DD V IN =V CE =5.0V, V OUT =V OUT(E) 1.1V A Stand-by Current I STB V IN =5.0V, V CE =0V, V OUT =V OUT(E) 1.1V A Oscillation Frequency PFM Switching Current f OSC I PFM V IN =V OUT(E) +2.0V, V CE =1.0V, I OUT =100mA khz (*12) ma V IN =V OUT(E) +2.0V, V CE =V IN, I OUT =1mA PFM Duty Limit DTY LIMIT_PFM V CE =V IN =(C-1), I OUT =1mA (*12) % Maximum Duty Cycle DTY MAX V IN =V CE =5.0V, V OUT =V OUT(E) 0.9V % Minimum Duty Cycle DTY MIN V IN =V CE =5.0V, V OUT =V OUT(E) 1.1V % Efficiency (*2) EFFI % V CE =V IN =V OUT(E) +1.2V, I OUT =100mA Lx SW "H" ON Resistance 1 R LxH V IN =V CE =5.0V, V OUT =0V, I Lx =100mA (*3) Lx SW "H" ON Resistance 2 R LxH V IN =V CE =3.6V, V OUT =0V, I Lx =100mA (*3) Lx SW "L" ON Resistance 1 R LxL V IN =V CE =5.0V (*4) Lx SW "L" ON Resistance 2 R LxL V IN =V CE =3.6V (*4) Lx SW "H" Leak Current (*5) I LEAKH V IN =V OUT =5.0V, V CE =0V, Lx=0V A Lx SW "L" Leak Current (*5) I LEAKL V IN =V OUT =5.0V, V CE =0V, Lx=5.0V A Current Limit (*10) I LIM V IN =V CE =5.0V, V OUT =V OUT(E) 0.9V (*8) ma Output Voltage Temperature Characteristics CE "H" Voltage CE "L" Voltage PWM "H" Level Voltage V OUT / (V OUT Topr) V CEH V CEL V PWMH I OUT =30mA, -40Topr ppm/ V OUT =0V, Applied voltage to V CE, (*11) Voltage changes Lx to H level V V OUT =0V, Applied voltage to V CE, Voltage changes Lx to L level (*11) V SS V I OUT =1mA (*6), Voltage which oscillation frequency - - V IN V becomes 1020 khzf OSC 1380kHz (*13) PWM "L" Level Voltage V PWML I OUT =1mA (*6) V, Voltage which oscillation frequency IN becomes f OSC 1020kHz (*13) V CE "H" Current I CEH V IN =V CE =5.0V, V OUT =0V A CE "L" Current I CEL V IN =5.0V, V CE =0V, V OUT =0V A Soft Start Time t SS V CE =0V V IN, I OUT =1mA ms Latch Time t LAT V IN =V CE =5.0V, V OUT =0.8V OUT(E), Short Lx at 1 resistance (*7) ms Short Protection Threshold Voltage V SHORT Sweeping V OUT, V IN =V CE =5.0V, Short Lx at 1 resistance, V OUT voltage which Lx becomes L level within 1ms V Test conditions: Unless otherwise stated, V IN =5.0V, V OUT(E) =Nominal Voltage NOTE: *1: Including hysteresis operating voltage range. *2: EFFI = { ( output voltageoutput current ) ( input voltageinput current) }100 *3: ON resistance ()= (V IN - Lx pin measurement voltage) 100mA *4: R&D value *5: When temperature is high, a current of approximately 10A (maximum) may leak. *6: The CE/MODE pin of the XC9237A series works also as an external switching pin of PWM control and PWM/PFM control. When the IC is in the operation, control is switched to the automatic PWM/PFM switching mode when the CE/MODE pin voltage is equal to or greater than V IN minus 0.3V, and to the PWM mode when the CE/MODE pin voltage is equal to or lower than V IN minus 1.0V and equal to or greater than V CEH. *7: Time until it short-circuits V OUT with GND via 1of resistor from an operational state and is set to Lx=0V from current limit pulse generating. *8: When V IN is less than 2.4V, limit current may not be reached because voltage falls caused by ON resistance. *9: When the difference between the input and the output is small, some cycles may be skipped completely before current maximizes. If current is further pulled from this state, output voltage will decrease because of P-ch driver ON resistance. *10: Current limit denotes the level of detection at peak of coil current. *11: H =V IN ~V IN -1.2V, L =+0.1V~-0.1V *12: XC9235 series exclude I PFM and DTY LIMIT_PFM because those are only for the PFM control s functions. *13: XC9235/XC9236 series exclude V PWMH and V PWML because those are only for the XC9237 series functions. 5/34

6 XC9235/XC9236/XC9237 Series ELECTRICAL CHARACTERISTICS (Continued) XC9235A18Dxx/XC9236A18Dxx/XC9237A18Dxx, V OUT =1.8V, f OSC =3.0MHz, Ta=25 6/34 PARAMETER SYMBOL CONDITIONS MIN. TYP. MAX. UNIT CIRCUIT Output Voltage V OUT V IN =V CE =5.0V, I OUT =30mA V Operating Voltage Range V IN V Maximum Output Current UVLO Voltage I OUTMAX V UVLO V IN =V OUT(E) +2.0V, V CE =1.0V, When connected to external components (*9) ma V CE =V IN, V OUT =0V, Voltage which Lx pin holding L level (*1,*11) V Supply Current I DD V IN =V CE =5.0V, V OUT =V OUT(E) 1.1V A Stand-by Current I STB V IN =5.0V, V CE =0V, V OUT =V OUT(E) 1.1V A Oscillation Frequency PFM Switching Current f OSC I PFM V IN =V OUT(E) +2.0V, V CE =1.0V, I OUT =100mA khz V IN =V OUT(E) +2.0V, V CE =V IN, I OUT =1mA (*12) ma PFM Duty Limit DTY LIMIT_PFM V CE =V IN =(C-1), I OUT =1mA (*12) % Maximum Duty Cycle DTY MAX V IN =V CE =5.0V, V OUT =V OUT(E) 0.9V % Minimum Duty Cycle DTY MIN V IN =V CE =5.0V, V OUT =V OUT(E) 0.1V % Efficiency (*2) EFFI % V CE =V IN V OUT(E) +1.2V, I OUT =100mA Lx SW "H" ON Resistance 1 R LxH V IN =V CE =5.0V, V OUT =0V, I Lx =100mA (*3) Lx SW "H" ON Resistance 2 R LxH V IN =V CE =3.6V, V OUT =0V, I Lx =100mA (*3) Lx SW "L" ON Resistance 1 R LxL V IN =V CE =5.0V (*4) Lx SW "L" ON Resistance 2 R LxL V IN =V CE =3.6V (*4) Lx SW "H" Leak Current (*5) I LEAKH V IN =V OUT =5.0V, V CE =0V, Lx=0V A Lx SW "L" Leak Current (*5) I LEAKL V IN =V OUT =5.0V, V CE =0V, Lx=5.0V A Current Limit (*10) I LIM V IN =V CE =5.0V, V OUT =V OUT(E) 0.9V (*8) ma Output Voltage V OUT / I OUT =30mA, -40Topr ppm/ Temperature Characteristics (V OUT Topr) V CE "H" Voltage V OUT =0V, Applied voltage to V CE, CEH Voltage changes Lx to H level (*11) V CE "L" Voltage PWM "H" Level Voltage V CEL V PWMH V OUT =0V, Applied voltage to V CE, Voltage changes Lx to L level (*11) V SS V I OUT =1mA (*6), Voltage which oscillation frequency - - V IN V becomes 2550kHzf OSC 3450kHz (*13) PWM "L" Level Voltage V PWML I OUT =1mA (*6) V, Voltage which oscillation frequency IN becomes f OSC 2550kHz (*13) V CE "H" Current I CEH V IN =V CE =5.0V, V OUT =0V A CE "L" Current I CEL V IN =5.0V, V CE =0V, V OUT =0V A Soft Start Time t SS V CE =0V V IN, I OUT =1mA ms Latch Time t LAT V IN =V CE =5.0V, V OUT =0.8V OUT(E), Short Lx at 1 resistance (*7) ms Short Protection Threshold Voltage V SHORT Sweeping V OUT, V IN =V CE =5.0V, Short Lx at 1 resistance, V OUT voltage which Lx becomes L level within 1ms V Test conditions: Unless otherwise stated, V IN =5.0V, V OUT(E) =Nominal Voltage NOTE: *1: Including hysteresis operating voltage range. *2: EFFI = { ( output voltageoutput current ) ( input voltageinput current) }100 *3: ON resistance ()= (V IN - Lx pin measurement voltage) 100mA *4: R&D value *5: When temperature is high, a current of approximately 10A (maximum) may leak. *6: The CE/MODE pin of the XC9237A series works also as an external switching pin of PWM control and PWM/PFM control. When the IC is in the operation, control is switched to the automatic PWM/PFM switching mode when the CE/MODE pin voltage is equal to or greater than V IN minus 0.3V, and to the PWM mode when the CE/MODE pin voltage is equal to or lower than V IN minus 1.0V and equal to or greater than V CEH. *7: Time until it short-circuits V OUT with GND via 1of resistor from an operational state and is set to Lx=0V from current limit pulse generating. *8: When V IN is less than 2.4V, limit current may not be reached because voltage falls caused by ON resistance. *9: When the difference between the input and the output is small, some cycles may be skipped completely before current maximizes. If current is further pulled from this state, output voltage will decrease because of P-ch driver ON resistance. *10: Current limit denotes the level of detection at peak of coil current. *11: H =V IN ~V IN -1.2V, L =+0.1V~-0.1V *12: XC9235 series exclude I PFM and DTY LIMIT_PFM because those are only for the PFM control s functions. *13: XC9235/XC9236 series exclude V PWMH and V PWML because those are only for the XC9237 series functions.

7 ELECTRICAL CHARACTERISTICS (Continued) XC9235/XC9236/XC9237 Series XC9235B(C)(E)(G)18Cxx/XC9236B(C)(E)(G)18Cxx/XC9237B(C)(E)(G)18Cxx, V OUT =1.8V, f OSC =1.2MHz, Ta=25 PARAMETER SYMBOL CONDITIONS MIN. TYP. MAX. UNIT CIRCUIT Output Voltage V OUT V IN =V CE =5.0V, I OUT =30mA V Operating Voltage Range (B/C series) V IN Operating Voltage Range (E/G series) V Maximum Output Current I OUTMAX V IN =V OUT(E) +2.0V, V CE =1.0V, (*9) When connected to external components ma UVLO Voltage V UVLO V CE =V IN, V OUT =V OUT(E) 0.5V (*14) (*1, *11) Voltage which Lx pin holding L level V Supply Current I DD V IN =V CE =5.0V, V OUT =V OUT(E) 1.1V A Stand-by Current I STB V IN =5.0V, V CE =0V, V OUT =V OUT(E) 1.1V A Oscillation Frequency f OSC V IN =V OUT(E) +2.0V, V CE =1.0V, I OUT =100mA khz PFM Switching Current I PFM (*12) V IN =V OUT(E) +2.0V, V CE =V IN, I OUT =1mA ma PFM Duty Limit DTY LIMIT_PFM V CE =V IN =(C-1), I OUT =1mA (*12) % Maximum Duty Cycle DTY MAX V IN =V CE =5.0V, V OUT =V OUT(E) 0.9V % Minimum Duty Cycle DTY MIN V IN =V CE =5.0V, V OUT =V OUT(E) 1.1V % Efficiency (*2) EFFI % V CE =V IN =V OUT(E) +1.2V, I OUT =100mA Lx SW "H" ON Resistance 1 R LxH V IN =V CE =5.0V, V OUT (E) 0.9V, I Lx =100mA (*3) Lx SW "H" ON Resistance 2 R LxH V IN =V CE =3.6V, V OUT (E) 0.9V, I Lx =100mA (*3) Lx SW "L" ON Resistance 1 R LxL V IN =V CE =5.0V (*4) Lx SW "L" ON Resistance 2 R LxL V IN =V CE =3.6V (*4) Lx SW "H" Leak Current (*5) I LEAKH V IN =V OUT =5.0V, V CE =0V, Lx=0V A Current Limit (*10) I LIM V IN =V CE =5.0V, V OUT =V OUT(E) 0.9V (*8) ma Output Voltage V OUT / Temperature Characteristics (V OUT Topr) I OUT =30mA, -40Topr ppm/ CE "H" Voltage V CEH V OUT = V OUT(E) 0.9V, Applied voltage to V CE, (*11) Voltage changes Lx to H level V CE "L" Voltage V CEL V OUT = V OUT(E) 0.9V, Applied voltage to V CE, Voltage changes Lx to L level (*11) V SS V PWM "H" Level Voltage V PWMH I OUT =1mA (*6), Voltage which oscillation frequency - - V IN V becomes 1020 khzf OSC 1380kHz (*13) PWM "L" Level Voltage V PWML I OUT =1mA (*6) V, Voltage which oscillation frequency IN becomes f OSC 1020kHz (*13) V CE "H" Current I CEH V IN =V CE =5.0V, V OUT = V OUT(E) 0.9V A CE "L" Current I CEL V IN =5.0V, V CE =0V, V OUT = V OUT(E) 0.9V A Soft Start Time (B/G Series) t SS V CE =0V V IN, I OUT =1mA ms Soft Start Time (C/E Series) t SS V CE =0V V IN, I OUT =1mA ms Latch Time V IN =V CE =5.0V, V OUT =0.8V OUT(E), (*7) ms Short Protection Threshold Voltage (B/C Series) Short Protection Threshold Voltage (E/G Series) t LAT V SHORT V SHORT Short Lx at 1 resistance Sweeping V OUT, V IN =V CE =5.0V, Short Lx at 1 resistance, V OUT voltage which Lx becomes L level within 1ms V IN =V CE =5.0V, The V OUT at Lx= Low" (*11) while decreasing V OUT from V OUT (E) 0.4V V V C L Discharge R DCHG V IN =5.0V, L X =5.0V, V CE =0V, V OUT =open Test conditions: Unless otherwise stated, V IN =5.0V, V OUT(E) =Nominal Voltage, applied voltage sequence is V OUT V IN V CE NOTE: *1: Including hysteresis operating voltage range. *2: EFFI = { ( output voltageoutput current ) ( input voltageinput current) }100 *3: ON resistance ()= (V IN - Lx pin measurement voltage) 100mA *4: R&D value *5: When temperature is high, a current of approximately 10A (maximum) may leak. *6: The CE/MODE pin of the XC9237A series works also as an external switching pin of PWM control and PWM/PFM control. When the IC is in the operation, control is switched to the automatic PWM/PFM switching mode when the CE/MODE pin voltage is equal to or greater than V IN minus 0.3V, and to the PWM mode when the CE/MODE pin voltage is equal to or lower than V IN minus 1.0V and equal to or greater than V CEH. *7: Time until it short-circuits V OUT with GND via 1of resistor from an operational state and is set to Lx=0V from current limit pulse generating. *8: When V IN is less than 2.4V, limit current may not be reached because voltage falls caused by ON resistance. *9: When the difference between the input and the output is small, some cycles may be skipped completely before current maximizes. If current is further pulled from this state, output voltage will decrease because of P-ch driver ON resistance. *10: Current limit denotes the level of detection at peak of coil current. *11: H =V IN ~V IN -1.2V, L =+0.1V~-0.1V *12: XC9235 series exclude I PFM and DTY LIMIT_PFM because those are only for the PFM control s functions. *13: XC9235/XC9236 series exclude V PWMH and V PWML because those are only for the XC9237 series functions. *14: V IN is applied when V OUT (E) x 0.5V becomes more than V IN. 7/34

8 8/34 XC9235/XC9236/XC9237 Series ELECTRICAL CHARACTERISTICS (Continued) XC9235B(C)(E)(G)18Dxx/XC9236B(C)(E)(G)18Dxx/XC9237B(C)(E)(G)18Dxx, V OUT =1.8V, f OSC =3.0MHz, Ta=25 PARAMETER SYMBOL CONDITIONS MIN. TYP. MAX. UNIT CIRCUIT Output Voltage V OUT V IN =V CE =5.0V, I OUT =30mA V Operating Voltage Range (B/C series) V IN Operating Voltage Range (E/G series) V Maximum Output Current I OUTMAX V IN =V OUT(E) +2.0V, V CE =1.0V, (*9) When connected to external components ma UVLO Voltage V UVLO V CE =V IN, V OUT =V OUT(E) 0.5V (*14), (*1,*11) Voltage which Lx pin holding L level V Supply Current I DD V IN =V CE =5.0V, V OUT =V OUT(E) 1.1V A Stand-by Current I STB V IN =5.0V, V CE =0V, V OUT =V OUT(E) 1.1V A Oscillation Frequency f OSC V IN =V OUT(E) +2.0V, V CE =1.0V, I OUT =100mA khz PFM Switching Current I PFM (*12) V IN =V OUT(E) +2.0V, V CE =V IN, I OUT =1mA ma PFM Duty Limit DTY LIMIT_PFM V CE =V IN =(C-1), I OUT =1mA (*12) % Maximum Duty Cycle DTY MAX V IN =V CE =5.0V, V OUT =V OUT(E) 0.9V % Minimum Duty Cycle DTY MIN V IN =V CE =5.0V, V OUT =V OUT(E) 0.1V % Efficiency (*2) EFFI % V CE =V IN V OUT(E) +1.2V, I OUT =100mA Lx SW "H" ON Resistance 1 R LxH V IN =V CE =5.0V, V OUT =V OUT(E) 0.9V, I Lx =100mA (*3) Lx SW "H" ON Resistance 2 R LxH V IN =V CE =3.6V, V OUT =V OUT(E) 0.9V, I Lx =100mA (*3) Lx SW "L" ON Resistance 1 R LxL V IN =V CE =5.0V (*4) Lx SW "L" ON Resistance 2 R LxL V IN =V CE =3.6V (*4) Lx SW "H" Leak Current (*5) I LEAKH V IN =V OUT =5.0V, V CE =0V, Lx=0V A Current Limit (*10) I LIM V IN =V CE =5.0V, V OUT =V OUT(E) 0.9V (*8) ma Output Voltage V OUT / Temperature Characteristics (V OUT Topr) I OUT =30mA, -40Topr ppm/ CE "H" Voltage V CEH V OUT =V OUT(E) 0.9V, Applied voltage to V CE, (*11) Voltage changes Lx to H level V CE "L" Voltage V CEL V OUT =V OUT(E) 0.9V, Applied voltage to V CE, Voltage changes Lx to L level (*11) V SS V PWM "H" Level Voltage V PWMH I OUT =1mA (*6), Voltage which oscillation frequency - - V IN V becomes 2550kHzf OSC 3450kHz (*13) PWM "L" Level Voltage V PWML I OUT =1mA (*6) V, Voltage which oscillation frequency IN becomes f OSC 2550kHz (*13) V CE "H" Current I CEH V IN =V CE =5.0V, V OUT =V OUT(E) 0.9V A CE "L" Current I CEL V IN =5.0V, V CE =0V, V OUT =V OUT(E) 0.9V A Soft Start Time (B/G Series) t SS V CE =0V V IN, I OUT =1mA ms Soft Start Time (C/E Series) t SS V CE =0V V IN, I OUT =1mA ms Latch Time t LAT V IN =V CE =5.0V, V OUT =0.8V OUT(E), (*7) Short Lx at 1 resistance ms Short Protection Threshold Voltage (B/C Series) Short Protection Threshold Voltage (E/G Series) V SHORT V SHORT Sweeping V OUT, V IN =V CE =5.0V, Short Lx at 1 resistance, V OUT voltage which Lx becomes L level within 1ms V IN =V CE =5.0V, The V OUT at Lx= Low" (*11) while decreasing V OUT from V OUT (E) 0.4V V V C L Discharge R DCHG V IN =5.0V, L X =5.0V, V CE =0V, V OUT =open Test conditions: Unless otherwise stated, V IN =5.0V, V OUT(E) =Nominal Voltage, applied voltage sequence is V OUT V IN V CE NOTE: *1: Including hysteresis operating voltage range. *2: EFFI = { ( output voltageoutput current ) ( input voltageinput current) }100 *3: ON resistance ()= (V IN - Lx pin measurement voltage) 100mA *4: R&D value *5: When temperature is high, a current of approximately 10A (maximum) may leak. *6: The CE/MODE pin of the XC9237A series works also as an external switching pin of PWM control and PWM/PFM control. When the IC is in the operation, control is switched to the automatic PWM/PFM switching mode when the CE/MODE pin voltage is equal to or greater than V IN minus 0.3V, and to the PWM mode when the CE/MODE pin voltage is equal to or lower than V IN minus 1.0V and equal to or greater than V CEH. *7: Time until it short-circuits V OUT with GND via 1of resistor from an operational state and is set to Lx=0V from current limit pulse generating. *8: When V IN is less than 2.4V, limit current may not be reached because voltage falls caused by ON resistance. *9: When the difference between the input and the output is small, some cycles may be skipped completely before current maximizes. If current is further pulled from this state, output voltage will decrease because of P-ch driver ON resistance. *10: Current limit denotes the level of detection at peak of coil current. *11: H =V IN ~V IN -1.2V, L =+0.1V~-0.1V *12: XC9235 series exclude I PFM and DTY LIMIT_PFM because those are only for the PFM control s functions. *13: XC9235/XC9236 series exclude V PWMH and V PWML because those are only for the XC9237 series functions. *14: V IN is applied when V OUT (E) x 0.5V becomes more than V IN.

9 XC9235/XC9236/XC9237 Series ELECTRICAL CHARACTERISTICS (Continued) XC9235D(F)08Cxx/XC9236D(F)08Cxx/XC9237D(F)08Cxx, FB Type, f OSC =1.2MHz, Ta=25 PARAMETER SYMBOL CONDITIONS MIN. TYP. MAX. UNIT CIRCUIT FB Voltage V FB V IN = V CE =5.0V, The V FB at Lx= High" (*11) while decreasing FB pin voltage from 0.9V V Operating Voltage Range V IN V Maximum Output Current I OUTMAX V IN =3.2V, V CE =1.0V (*9) When connected to external components ma UVLO Voltage V UVLO V CE = V IN, V FB = 0.4V, (*1,*11) Voltage which Lx pin holding L level V Supply Current I DD V IN =V CE =5.0V, V FB = 0.88V - 15 A Stand-by Current I STB V IN =5.0V, V CE =0V, V FB = 0.88V A Oscillation Frequency f OSC V IN = 3.2V, V CE =1.0V, I OUT =100mA khz PFM Switching Current I PFM (*12) V IN =3.2V, V CE = V IN, I OUT =1mA ma PFM Duty Limit DTY LIMIT_PFM V CE = V IN =2.0V I OUT =1mA (*12) % Maximum Duty Cycle DTY MAX V IN = V CE =5.0V, V FB = 0.72V % Minimum Duty Cycle DTY MIN V IN = V CE =5.0V, V FB = 0.88V % Efficiency (*2) EFFI V CE = V IN 2.4V, I OUT = 100mA % Lx SW "H" ON Resistance 1 R LH V IN = V CE = 5.0V, V FB = 0.72V,IL X = 100mA (*3) Lx SW "H" ON Resistance 2 R LH V IN = V CE = 3.6V, V FB = 0.72V,IL X = 100mA (*3) Lx SW "L" ON Resistance 1 R LL V IN = V CE = 5.0V (*4) Lx SW "L" ON Resistance 2 R LL V IN = V CE = 3.6V (*4) Lx SW "H" Leak Current (*5) I LEAKH V IN = V FB = 5.0V, V CE = 0V, L X = 0V A Current Limit (*10) I LIM V IN = V CE = 5.0V, V FB = 0.72V (*8) ma Output Voltage V OUT / I OUT =30mA Temperature Characteristics (V OUT Topr) -40Topr ppm/ CE "H" Voltage V CEH V FB =0.72V, Applied voltage to V CE, (*11) Voltage changes Lx to H level V CE "L" Voltage V CEL V FB =0.72V, Applied voltage to V CE, Voltage changes Lx to L level (*11) V SS V PWM "H" Level Voltage V PWMH I OUT =1mA (*6), Voltage which oscillation frequency becomes 1020kHzf OSC 1380kHz (*13) - - V IN V PWM "L" Level Voltage V PWML I OUT =1mA (*6) V, Voltage which oscillation frequency IN - becomes f OSC 1020kHz (*13) V CE "H" Current I CEH V IN = V CE =5.0V, V FB =0.72V A CE "L" Current I CEL V IN =5.0V, V CE = 0V, V FB =0.72V A Soft Start Time (D series) t SS Soft Start Time (F series) V CE = 0V V IN, I OUT =1mA ms Latch Time t LAT V IN =V CE =5.0V, V FB =0.64, Short Lx at 1 (*7) resistance ms Short Protection Threshold Voltage V SHORT V IN = V CE =5.0V, The V FB at Lx= Low" (*11) while decreasing FB pin voltage from 0.4V V C L Discharge R DCHG V IN = 5.0V,L X = 5.0V, V CE = 0V, V FB = open Test conditions: V OUT =1.2V when the external components are connected. Unless otherwise stated, V IN =5.0V, V OUT(E) =Nominal Voltage, applied voltage sequence is V OUT V IN V CE NOTE: *1: Including hysteresis operating voltage range. *2: EFFI = { ( output voltageoutput current ) ( input voltageinput current) }100 *3: ON resistance ()= (V IN - Lx pin measurement voltage) 100mA *4: R&D value *5: When temperature is high, a current of approximately 10A (maximum) may leak. *6: The CE/MODE pin of the XC9237A series works also as an external switching pin of PWM control and PWM/PFM control. When the IC is in the operation, control is switched to the automatic PWM/PFM switching mode when the CE/MODE pin voltage is equal to or greater than V IN minus 0.3V, and to the PWM mode when the CE/MODE pin voltage is equal to or lower than V IN minus 1.0V and equal to or greater than V CEH. *7: Time until it short-circuits V FB with GND via 1of resistor from an operational state and is set to Lx=0V from current limit pulse generating. *8: When V IN is less than 2.4V, limit current may not be reached because voltage falls caused by ON resistance. *9: When the difference between the input and the output is small, some cycles may be skipped completely before current maximizes. If current is further pulled from this state, output voltage will decrease because of P-ch driver ON resistance. *10: Current limit denotes the level of detection at peak of coil current. *11: H =V IN ~V IN -1.2V, L =+0.1V~-0.1V *12: XC9235 series exclude I PFM and DTY LIMIT_PFM because those are only for the PFM control s functions. *13: XC9235/XC9236 series exclude V PWMH and V PWML because those are only for the XC9237 series functions. 9/34

10 XC9235/XC9236/XC9237 Series ELECTRICAL CHARACTERISTICS (Continued) XC9235D(F)08Dxx/XC9236D(F)08Dxx/XC9237D(F)08Dxx, FB, f OSC =3.0MHz, Ta=25 PARAMETER SYMBOL CONDITIONS MIN. TYP. MAX. UNIT CIRCUIT FB Voltage V FB V IN = V CE =5.0V, The V FB at Lx= High" (*11) while decreasing FB pin voltage from 0.9V V Operating Voltage Range V IN V Maximum Output Current UVLO Voltage I OUTMAX V UVLO V IN =3.2V, V CE =1.0V When connected to external components (*9) ma V CE = V IN, V FB = 0.4V, Voltage which Lx pin holding L level (*1, *11) V Supply Current I DD V IN =V CE =5.0V, V FB = 0.88V A Stand-by Current I STB V IN =5.0V, V CE =0V, V FB = 0.88V A Oscillation Frequency f OSC V IN = 3.2V, V CE =1.0V, I OUT =100mA khz PFM Switching Current I PFM (*12) V IN =3.2V, V CE = V IN, I OUT =1mA ma PFM Duty Limit DTY LIMIT_PFM V CE = V IN =2.2V I OUT =1mA (*12) % Maximum Duty Cycle DTY MAX V IN = V CE =5.0V, V FB = 0.72V % Minimum Duty Cycle DTY MIN V IN = V CE =5.0V, V FB = 0.88V % Efficiency (*2) EFFI V CE = V IN 2.4V, I OUT = 100mA % Lx SW "H" ON Resistance 1 R LH V IN = V CE = 5.0V, V FB = 0.72V,IL X = 100mA (*3) Lx SW "H" ON Resistance 2 R LH V IN = V CE = 3.6V, V FB = 0.72V,IL X = 100mA (*3) Lx SW "L" ON Resistance 1 R LL V IN = V CE = 5.0V (*4) Lx SW "L" ON Resistance 2 R LL V IN = V CE = 3.6V (*4) Lx SW "H" Leak Current (*5) I LEAKH V IN = V FB = 5.0V, V CE = 0V, L X = 0V A Current Limit (*10) I LIM V IN = V CE = 5.0V, V FB = 0.72V (*8) ma Output Voltage V OUT / I OUT =30mA Temperature Characteristics (V OUT Topr) -40Topr ppm/ CE "H" Voltage V CEH V FB =0.72V, V CE, Voltage changes Lx to H level (*11) V CE "L" Voltage V CEL V FB =0.72V, V CE, Voltage changes Lx to L level (*11) V SS V PWM "H" Level Voltage V PWMH I OUT = 1mA (*6), Voltage which oscillation frequency becomes 2550kHzf OSC 3450kHz (*13) - - V IN V PWM "L" Level Voltage V PWML I OUT = 1mA (*6) V, Voltage which oscillation frequency IN - becomes f OSC 2550kHz (*13) V CE "H" Current I CEH V IN = V CE =5.0V, V FB =0.72V A CE "L" Current I CEL V IN =5.0V, V CE = 0V, V FB =0.72V A Soft Start Time (D series) t SS Soft Start Time (F series) V CE = 0V V IN, I OUT =1mA ms Latch Time t LAT V IN = V CE = 5.0V, V FB = 0.64, Short Lx at 1 resistance (*7) ms Short Protection Threshold Voltage V SHORT V IN = V CE =5.0V, The V FB at Lx= Low" (*11) while decreasing FB pin voltage from 0.4V V C L Discharge R DCHG V IN = 5.0V,L X = 5.0V,V CE = 0V,V FB = open Test conditions: V OUT =1.2V when the external components are connected. Unless otherwise stated, V IN =5.0V, V OUT(E) =Nominal Voltage, applied voltage sequence is V OUT V IN V CE NOTE: *1: Including hysteresis operating voltage range. *2: EFFI = { ( output voltageoutput current ) ( input voltageinput current) }100 *3: ON resistance ()= (V IN - Lx pin measurement voltage) 100mA *4: R&D value *5: When temperature is high, a current of approximately 10A (maximum) may leak. *6: The CE/MODE pin of the XC9237A series works also as an external switching pin of PWM control and PWM/PFM control. When the IC is in the operation, control is switched to the automatic PWM/PFM switching mode when the CE/MODE pin voltage is equal to or greater than V IN minus 0.3V, and to the PWM mode when the CE/MODE pin voltage is equal to or lower than V IN minus 1.0V and equal to or greater than V CEH. *7: Time until it short-circuits V FB with GND via 1of resistor from an operational state and is set to Lx=0V from current limit pulse generating. *8: When V IN is less than 2.4V, limit current may not be reached because voltage falls caused by ON resistance. *9: When the difference between the input and the output is small, some cycles may be skipped completely before current maximizes. If current is further pulled from this state, output voltage will decrease because of P-ch driver ON resistance. *10: Current limit denotes the level of detection at peak of coil current. *11: H =V IN ~V IN -1.2V, L =+0.1V~-0.1V *12: XC9235 series exclude I PFM and DTY LIMIT_PFM because those are only for the PFM control s functions. *13: XC9235/XC9236 series exclude V PWMH and V PWML because those are only for the XC9237 series functions. 10/34

11 XC9235/XC9236/XC9237 Series ELECTRICAL CHARACTERISTICS (Continued) PFM Switching Current (I PFM ) by Oscillation Frequency and Setting Voltage SETTING VOLTAGE (ma) 1.2MHz 3.0MHz MIN. TYP. MAX. MIN. TYP. MAX. V OUT(E) 1.2V VV OUT(E) 1.75V VV OUT(E) Input Voltage (V IN ) for Measuring PFM Duty Limit (DTY LIMIT_PFM ) f OSC 1.2MHz 3.0MHz C-1 V OUT(E) +0.5V V OUT(E) +1.0V Minimum operating voltage is 2.0V. ex.) Although when V OUT(E) is 1.2V and f OSC is 1.2MHz, (C-1) should be 1.7V, (C-1) becomes 2.0V for the minimum operating voltage 2.0V. Soft-Start Time, Setting VoltageXC9235B(G)/XC9236B(G)/XC9237B(G) Series only (s) SERIES f OSC SETTING VOLTAGE 1.2MHz 0.8V OUT(E)< XC9235B(G)/XC9237B(G) 1.2MHz 1.5V OUT(E)< MHz 1.8V OUT(E)< MHz 2.5V OUT(E)< XC9236B(G) 1.2MHz 0.8V OUT(E)< MHz 2.5V OUT(E)< XC9235B(G)/ 3.0MHz 0.8V OUT(E)< XC9236B(G)/XC9237B(G) 3.0MHz 1.8V OUT(E)< /34

12 XC9235/XC9236/XC9237 Series TYPICAL APPLICATION CIRCUIT XC9235/XC9236/XC9237A, B, C, E, G Series (Output Voltage Fixed) f OSC =3.0MHz L: 1.5H (NR3015, TAIYO YUDEN) C IN : 4.7F (Ceramic) C L : 10F (Ceramic) f OSC =1.2MHz L: 4.7H (NR4018, TAIYO YUDEN) C IN : 4.7F (Ceramic) C L : 10F (Ceramic) XC9235/XC9236/XC9237D, F Series (Output Voltage External Setting) <Setting for Output Voltage> Output voltage can be set externally by adding two resistors to the FB pin. The output voltage is calculated by the R FB1 and R FB2 value.the total of R FB1 and R FB2 is usually selected less than 1MΩ. Output voltages can be set in the range of 0.9V to 0.6V by use of 0.8V2.0% reference voltage. However, when input voltage (V IN ) is lower than the setting output voltage, output voltage (V OUT ) can not be higher than the input voltage (V IN ). V OUT =0.8 (R FB1 +R FB2 )/R FB2 The value of the phase compensation speed-up capacitor C FB is calculated by the formula of f ZFB = 1/(2 C FB R FB1 ) with f ZFB <10kHz. For optimization, f ZFB can be adjusted in the range of 1kHz to 20kHz depending on the inductance L and the load capacitance C L which are used. Formula When R FB1 =470kΩ and R FB2 =150k, V OUT1 =0.8 (470k+150k) / 150k=3.3V Example V OUT RFB1 RFB2 CFB V OUT RFB1 RFB2 CFB (V) (kω) (kω) (pf) (V) (kω) (kω) (pf) /34

13 XC9235/XC9236/XC9237 Series OPERATIONAL DESCRIPTION The XC9235/XC9236/XC9237 series consists of a reference voltage source, ramp wave circuit, error amplifier, PWM comparator, phase compensation circuit, output voltage adjustment resistors, P-channel MOS driver transistor, N-channel MOS switching transistor for the synchronous switch, current limiter circuit, UVLO circuit and others. (See the block diagram above.) The series ICs compare, using the error amplifier, the voltage of the internal voltage reference source with the feedback voltage from the VOUT pin through split resistors, R1 and R2. Phase compensation is performed on the resulting error amplifier output, to input a signal to the PWM comparator to determine the turn-on time during PWM operation. The PWM comparator compares, in terms of voltage level, the signal from the error amplifier with the ramp wave from the ramp wave circuit, and delivers the resulting output to the buffer driver circuit to cause the Lx pin to output a switching duty cycle. This process is continuously performed to ensure stable output voltage. The current feedback circuit monitors the P-channel MOS driver transistor current for each switching operation, and modulates the error amplifier output signal to provide multiple feedback signals. This enables a stable feedback loop even when a low ESR capacitor such as a ceramic capacitor is used ensuring stable output voltage. <Reference Voltage Source> The reference voltage source provides the reference voltage to ensure stable output voltage of the DC/DC converter. <Ramp Wave Circuit> The ramp wave circuit determines switching frequency. The frequency is fixed internally and can be selected from 1.2MHz or 3.0MHz. Clock pulses generated in this circuit are used to produce ramp waveforms needed for PWM operation, and to synchronize all the internal circuits. <Error Amplifier> The error amplifier is designed to monitor output voltage. The amplifier compares the reference voltage with the feedback voltage divided by the internal split resistors, R1 and R2. When a voltage lower than the reference voltage is fed back, the output voltage of the error amplifier increases. The gain and frequency characteristics of the error amplifier output are fixed internally to deliver an optimized signal to the mixer. <Current Limit> The current limiter circuit of the XC9235/XC9236/XC9237 series monitors the current flowing through the P-channel MOS driver transistor connected to the Lx pin, and features a combination of the current limit mode and the operation suspension mode. When the driver current is greater than a specific level, the current limit function operates to turn off the pulses from the Lx pin at any given timing. When the driver transistor is turned off, the limiter circuit is then released from the current limit detection state. At the next pulse, the driver transistor is turned on. However, the transistor is immediately turned off in the case of an over current state. When the over current state is eliminated, the IC resumes its normal operation. The IC waits for the over current state to end by repeating the steps through. If an over current state continues for a few ms and the above three steps are repeatedly performed, the IC performs the function of latching the OFF state of the driver transistor, and goes into operation suspension mode. Once the IC is in suspension mode, operations can be resumed by either turning the IC off via the CE/MODE pin, or by restoring power to the V IN pin. The suspension mode does not mean a complete shutdown, but a state in which pulse output is suspended; therefore, the internal circuitry remains in operation. The current limit of the XC9235/XC9236/XC9237 series can be set at 1050mA at typical. Besides, care must be taken when laying out the PC Board, in order to prevent misoperation of the current limit mode. Depending on the state of the PC Board, latch time may become longer and latch operation may not work. In order to avoid the effect of noise, the board should be laid out so that input capacitors are placed as close to the IC as possible. 13/34

14 XC9235/XC9236/XC9237 Series OPERATIONAL DESCRIPTION (Continued) <Short-Circuit Protection> The short-circuit protection circuit monitors the internal R1 and R2 divider voltage from the V OUT pin (refer to FB point in the block diagram shown in the previous page). In case where output is accidentally shorted to the Ground and when the FB point voltage decreases less than half of the reference voltage (Vref) and a current more than the I LIM flows to the Pch MOS driver transistor, the short-circuit protection quickly operates to turn off and to latch the driver transistor. For the D/E/F/G series, it does not matter how much the current limit, once the FB voltage become less than the quarter of reference voltage (V REF ), the short-circuit protection operates to latch the Pch MOS driver transistor. In latch mode, the operation can be resumed by either turning the IC off and on via the CE/MODE pin, or by restoring power supply to the V IN pin. When sharp load transient happens, a voltage drop at the V OUT is propagated to the FB point through C FB, as a result, short circuit protection may operate in the voltage higher than 1/2 V OUT voltage. <UVLO Circuit> When the VIN pin voltage becomes 1.4V or lower, the Pch MOS driver transistor output driver transistor is forced OFF to prevent false pulse output caused by unstable operation of the internal circuitry. When the V IN pin voltage becomes 1.8V or higher, switching operation takes place. By releasing the UVLO function, the IC performs the soft start function to initiate output startup operation. The soft start function operates even when the VIN pin voltage falls momentarily below the UVLO operating voltage. The UVLO circuit does not cause a complete shutdown of the IC, but causes pulse output to be suspended; therefore, the internal circuitry remains in operation. <PFM Switch Current> In PFM control operation, until coil current reaches to a specified level (IPFM), the IC keeps the Pch MOS driver transistor on. In this case, time that the Pch MOS driver transistor is kept on (TON) can be given by the following formula. t ON = LIPFM / (VINVOUT) IPFM < PFM Duty Limit > In PFM control operation, the PFM duty limit (DTY LIMIT_PFM ) is set to 200% (TYP.). Therefore, under the condition that the duty increases (e.g. the condition that the step-down ratio is small), it s possible for Pch MOS driver transistor to be turned off even when coil current doesn t reach to IPFM. IPFM 14/34

15 XC9235/XC9236/XC9237 Series OPERATIONAL DESCRIPTION (Continued) C L High Speed Discharge XC9235B(C)(D)(E)(F)(G)/ XC9236B(C)(D)(E)(F)(G)/ XC9237B(C)(D)(E)(F)(G) series can quickly discharge the electric charge at the output capacitor (C L ) when a low signal to the CE pin which enables a whole IC circuit put into OFF state, is inputted via the Nch MOS switch transistor located between the L X pin and the V SS pin. When the IC is disabled, electric charge at the output capacitor (C L ) is quickly discharged so that it may avoid application malfunction. Discharge time of the output capacitor (C L ) is set by the C L auto-discharge resistance (R) and the output capacitor (C L ). By setting time constant of a C L auto-discharge resistance value [R] and an output capacitor value (C L ) as (=C x R), discharge time of the output voltage after discharge via the N channel transistor is calculated by the following formulas. V = V OUT(E) x e t/ or t=ln (V OUT(E) / V) V : Output voltage after discharge V OUT(E) : Output voltage t: Discharge time : C x R C= Capacitance of Output capacitor (C L ) R= C L auto-discharge resistance 15/34

16 XC9235/XC9236/XC9237 Series OPERATIONAL DESCRIPTION (Continued) <CE/MODE Pin Function> The operation of the XC9235/XC9236/XC9237 series will enter into the shut down mode when a low level signal is input to the CE/MODE pin. During the shutdown mode, the current consumption of the IC becomes 0A (TYP.), with a state of high impedance at the Lx pin and VOUT pin. The IC starts its operation by inputting a high level signal to the CE/MODE pin. The input to the CE/MODE pin is a CMOS input and the sink current is 0A (TYP.). XC9235/XC9236 series - Examples of how to use CE/MODE pin (A) SWCE ON OFF STATUS Stand-by Operation (B) SWCE STATUS ON OFF Operation Stand-by (A) (B) XC9237 series - Examples of how to use CE/MODE pin (A) SWCE SWPWM/PFM STATUS ON * PWM/PFM Automatic Switching Control OFF ON PWM Control OFF OFF Stand-by (B) SWCE SWPWM/PFM STATUS ON * Stand-by OFF ON PWM Control OFF OFF PWM/PFM Automatic Switching Control (A) (B) Intermediate voltage can be generated by RM1 and RM2. Please set the value of each R1, R2, RM1, RM2 from few hundreds k to few hundreds M. For switches, CPU open-drain I/O port and transistor can be used. 16/34

17 XC9235/XC9236/XC9237 Series OPERATIONAL DESCRIPTION (Continued) Soft Start Soft start time is available in two options via product selection. The A,C,D,and E types of XC9235/XC9236/XC9237 series provide 1.0ms (TYP). The B,F, and G types of XC9235/ XC9236/XC9237 series provide 0.25ms (TYP). However, for the D/F the soft-start time can be set by the external components. Soft start time is defined as the time interval to reach 90% of the output voltage from the time when the CE pin is turned on. 90% of setting voltage FUNCTION CHART CE/MODE OPERATIONAL STATES VOLTAGE LEVEL XC9235 XC9236 XC9237 H Level (*1) Synchronous PWM Fixed Control Synchronous PWM/PFM Automatic Switching M Level (*2) Synchronous PWM/PFM Automatic Switching Synchronous PWM Fixed Control L Level (*3) Stand-by Stand-by Stand-by Note on CE/MODE pin voltage level range (*1) H level: 0.65V < V CE / MODE < 6.0V (for XC9235/XC9236) H level: V IN 0.25V < V CE / MODE < V IN (for XC9237) (*2) M level: 0.65V < V CE / MODE < V IN - 1.0V (for XC9237) (*3) L level: 0V < V CE / MODE < 0.25V 17/34

18 XC9235/XC9236/XC9237 Series NOTE ON USE 1. For temporary, transitional voltage drop or voltage rising phenomenon, the IC is liable to malfunction should the ratings be exceeded. 2. The XC9235/XC9236/XC9237 series is designed for use with ceramic output capacitors. If, however, the potential difference is too large between the input voltage and the output voltage, a ceramic capacitor may fail to absorb the resulting high switching energy and oscillation could occur on the output. If the input-output potential difference is large, connect an electrolytic capacitor in parallel to compensate for insufficient capacitance. 3. Spike noise and ripple voltage arise in a switching regulator as with a DC/DC converter. These are greatly influenced by external component selection, such as the coil inductance, capacitance values, and board layout of external components. Once the design has been completed, verification with actual components should be done. 4. Depending on the input-output voltage differential, or load current, some pulses may be skipped, and the ripple voltage may increase. 5. When the difference between VIN and VOUT is large in PWM control, very narrow pulses will be outputted, and there is the possibility that some cycles may be skipped completely. 6. When the difference between VIN and VOUT is small, and the load current is heavy, very wide pulses will be outputted and there is the possibility that some cycles may be skipped completely. 7. With the IC, the peak current of the coil is controlled by the current limit circuit. Since the peak current increases when dropout voltage or load current is high, current limit starts operation, and this can lead to instability. When peak current becomes high, please adjust the coil inductance value and fully check the circuit operation. In addition, please calculate the peak current according to the following formula: Ipk = (VIN - VOUT) x OnDuty / (2 x L x f OSC ) + IOUT L: Coil Inductance Value f OSC : Oscillation Frequency 8. When the peak current which exceeds limit current flows within the specified time, the built-in Pch MOS driver transistor turns off. During the time until it detects limit current and before the built-in transistor can be turned off, the current for limit current flows; therefore, care must be taken when selecting the rating for the external components such as a coil. 9. When VIN is less than 2.4V, limit current may not be reached because voltage falls caused by ON resistance. 10. Care must be taken when laying out the PC Board, in order to prevent misoperation of the current limit mode. Depending on the state of the PC Board, latch time may become longer and latch operation may not work. In order to avoid the effect of noise, the board should be laid out so that input capacitors are placed as close to the IC as possible. 11. Use of the IC at voltages below the recommended voltage range may lead to instability. 12. This IC should be used within the stated absolute maximum ratings in order to prevent damage to the device. 13. When the IC is used in high temperature, output voltage may increase up to input voltage level at no load because of the leak current of the driver transistor. 14. The current limit is set to 1350mA (MAX.) at typical. However, the current of 1350mA or more may flow. In case that the current limit functions while the VOUT pin is shorted to the GND pin, when Pch MOS driver transistor is ON, the potential difference for input voltage will occur at both ends of a coil. For this, the time rate of coil current becomes large. By contrast, when Nch MOS driver transistor is ON, there is almost no potential difference at both ends of the coil since the VOUT pin is shorted to the GND pin. Consequently, the time rate of coil current becomes quite small. According to the repetition of this operation, and the delay time of the circuit, coil current will be converged on a certain current value, exceeding the amount of current, which is supposed to be limited originally. Even in this case, however, after the over current state continues for several ms, the circuit will be latched. A coil should be used within the stated absolute maximum rating in order to prevent damage to the device. Current flows into Pch MOS driver transistor to reach the current limit (ILIM). The current of ILIM or more flows since the delay time of the circuit occurs during from the detection of the current limit to OFF of Pch MOS driver transistor. Because of no potential difference at both ends of the coil, the time rate of coil current becomes quite small. Lx oscillates very narrow pulses by the current limit for several ms. The circuit is latched, stopping its operation. 18/34

19 XC9235/XC9236/XC9237 Series NOTE ON USE (Continued) 15. In order to stabilize V IN s voltage level and oscillation frequency, we recommend that a by-pass capacitor (CIN) be connected as close as possible to the VIN & VSS pins. 16. High step-down ratio and very light load may lead an intermittent oscillation. 17. During PWM / PFM automatic switching mode, operating may become unstable at transition to continuous mode. Please verify with actual parts. 18. Please note the inductance value of the coil. The IC may enter unstable operation if the combination of ambient temperature, setting voltage, oscillation frequency, and L value are not adequate. In the operation range close to the maximum duty cycle, The IC may happen to enter unstable output voltage operation even if using the L values listed below. <External Components> The Range of L Value f OSC V OUT L Value 3.0MHz 0.8VV OUT <4.0V 1.0H2.2H 1.2MHz V OUT 2.5V 2.5VV OUT 3.3H6.8H 4.7H6.8H *When a coil less value of 4.7μH is used at f OSC =1.2MHz or when a coil less value of 1.5μH is used at f OSC =3.0MHz, peak coil current more easily reach the current limit ILMI. In this case, it may happen that the IC can not provide 600mA output current. 19. It may happen to enter unstable operation when the IC goes into continuous operation mode under the condition of large input-output voltage difference. Care must be taken with the actual design unit. <External Components> 20. Torex places an importance on improving our products and their reliability. We request that users incorporate fail-safe designs and post-aging protection treatment when using Torex products in their systems. 19/34

20 XC9235/XC9236/XC9237 Series NOTE ON USE (Continued) 21. Instructions of pattern layouts (1) In order to stabilize V IN voltage level, we recommend that a by-pass capacitor (C IN ) be connected as close as possible to the V IN & V SS pins. (2) Please mount each external component as close to the IC as possible. (3) Wire external components as close to the IC as possible and use thick, short connecting traces to reduce the circuit impedance. (4) Make sure that the PCB GND traces are as thick as possible, as variations in ground potential caused by high ground currents at the time of switching may result in instability of the IC. (5) This series internal driver transistors bring on heat because of the output current and ON resistance of driver transistors. 22. NOTE ON MOUNTING (WLP-5-03) (1) Mount pad design should be optimized for user's conditions. (2) Sn-AG-Cu is used for the package terminals. If eutectic solder is used, mounting reliability is decreased. Please do not use eutectic solder paste. (3) When underfill agent is used to increase interfacial bonding strength, please take enough evaluation for selection. Some underfill materials and applied conditions may decrease bonding reliability. (4) The IC has exposed surface of silicon material in the top marking face and sides so that it is weak against mechanical damages. Please take care of handling to avoid cracks and breaks. (5) The IC has exposed surface of silicon material in the top marking face and sides. Please use the IC with keeping the circuit open (avoiding short-circuit from the out). (6) Semi-transparent resin is coated on the circuit face of the package. Please be noted that the usage under strong lights may affects device performance. 20/34

21 21/34 XC9235/XC9236/XC9237 Series TEST CIRCUITS

22 XC9235/XC9236/XC9237 Series TYPICAL PERFORMANCE CHARACTERISTICS (1) Efficiency vs. Output Current Efficency:EFFI(%) Efficiency: EFFI XC9237A18C L=4.7H (NR40Ambient Temperature: Ta () PWM/PFM Automatic Sw itching Control 2.4V VIN= 4.2V 3.6V PWM Control VIN= 4.2V 3.6V 2.4V Output Current: 10 IOUT (ma) Output Current:IOUT(mA) Efficiency: Efficency:EFFI(%) EFFI XC9237A18D L=1.5H (NR3015), CIN=4.7F, CL=10F 100 PWM/PFM Automatic Sw itching Control VIN= 4.2V V V PWM Control 40 VIN= 4.2V V 2.4V Output Current: 10IOUT (ma) Output Current:IOUT(mA) (2) Output Voltage vs. Output Current 2.1 XC923 Soft-Start Time, Setting 2.1 XC9237A18D L=1.5H (NR3015), CIN=4.7F, CL=10F Output Voltage:Vout(V) VOUT PWM/PFM Automatic Sw itching Control VIN4.2V,3.6V,2.4V PWM Control Output Voltage:Vout(V) PWM/PFM Automatic Sw itching Control VIN4.2V,3.6V,2.4V PWM Control Output Current: IOUT (ma) Output Current:IOUT(mA) Output Current: IOUT (ma) Output Current:IOUT(mA) (3) Ripple Voltage vs. Output Current 100 XC9237A18C L=4.7H (NR4018), CIN=4.7F, CL=10F 100 XC9237A18D L=1.5H (NR3015), CIN=4.7F, CL=10F Ripple Voltage:Vr(mV) Vr PWM Control VIN4.2V,3.6V,2.4V PWM/PFM Automatic Sw itching Control VIN4.2V 3.6V 2.4V Ripple Voltage:Vr(mV) PWM Control VIN4.2V,3.6V,2.4V PWM/PFM Automatic Sw itching Control VIN4.2V 3.6V 2.4V Output Current:IOUT(mA) Output Current:IOUT(mA) Supply 22/34

23 XC9235/XC9236/XC9237 Series TYPICAL PERFORMANCE CHARACTERISTICS (Continued) (4) Oscillation Frequency vs. Ambient Temperature 1.5 XC9237A18C L=4.7H (NR4018), CIN=4.7F, CL=10F 3.5 XC9237A18D L=1.5H (NR3015), CIN=4.7F, CL=10F Oscillation Frequency: FOSC : FOSC(MHz) VIN=3.6V Oscillation Frequency: FOSC : FOSC(MHz) VIN=3.6V Ambient Temperature: Ta Ta () () Ambient Temperature: Ta Ta () () (5) Supply Current vs. Ambient Temperature XC9237A18C XC9237A18D Supply Current: IDD : IDD (A) (μa) VIN=2.0V VIN=4.0V VIN=6.0V Supply Current: Current IDD : IDD (A) (μa) VIN=2.0V VIN=4.0V VIN=6.0V Ambient Temperature: Ta Ta () () Ambient Temperature: Ta Ta () () (6) Output Voltage vs. Ambient Temperature (7) UVLO Voltage vs. Ambient Temperature XC9237A18D XC9237A18D CE=VIN Output Voltage: : VOUT (V) (V) VIN=3.6V UVLO UVLO Voltage: : UVLO (V) Ambient Temperature: Ta Ta () () Ambient Temperature: Ta Ta () () 23/34

24 XC9235/XC9236/XC9237 Series TYPICAL PERFORMANCE CHARACTERISTICS (Continued) (8) CE "H" Voltage vs. Ambient Temperature (9) CE "L" Voltage vs. Ambient Temperature XC9237A18D XC9237A18D CE H Voltage: VCEH (V) CE "H" Voltage : VCEH (V) VIN=5.0V VIN=3.6V VIN=2.4V CE "L" L Voltage: VCEL : (V) (V) VIN=5.0V VIN=3.6V VIN=2.4V Ambient TempOutput Ambient Current: Temperature: IOUT (ma) Ta () Ambient Temperature: Ta Ta () () (10) Soft Start Time vs. Ambient Temperature XC9237A18C L=4.7H (NR4018), CIN=4.7F, CL=10F XC9237A18D L=1.5H (NR3015), CIN=4.7F, CL=10F 5 5 Soft Start Time: TSS : TSS (ms) (ms) VIN=3.6V Soft Start Time: TSS : (ms) (ms) VIN=3.6V AmbiRipple Voltage: Ambient Vr (mv) Temperature: Ta () Ambient Temperature: Ta Ta () () (11) "Pch / Nch" Driver on Resistance vs. Input Voltage Lx SW ON ON Resistance:RLxH,RLxL RLxH, RLxL () (Ω) XC9237A18D Nch on Resistance Pch on Resistance Input Voltage: VIN (V)<External Input Voltage Components> : VIN (V) 24/34

25 XC9235/XC9236/XC9237 Series TYPICAL PERFORMANCE CHARACTERISTICS (Continued) (12) XC9235B/36B/37B Rise Wave Form XC9237B12C L=4.7H (NR4018), CIN=4.7F, CL=10F VIN=5.0V IOUT=1.0mA VIN=5.0V IOUT=1.0mA XC9237B33D L=1.5H (NR3015), CIN=4.7F, CL=10F VOUT0.5V/div VOUT1.0V/div CE0.0V1.0V CE0.0V1.0V 100s/div 100s/div (13) XC9235B/36B/37B Soft-Start Time vs. Ambient Temperature XC9237B12C XC9237B33D L=4.7H(NR4018), CIN=4.7F, CL=10F L=1.5H(NR3015), CIN=4.7F, CL=10F (14) XC9235B/36B/37B CL Discharge Resistance vs. Ambient Temperature XC9237B33D 600 CL Discharge Resistance: () VIN=6.0V VIN=4.0V VIN=2.0V Ambient Temperature: Ta () 25/34